Skip to main content

Full text of "The Morphology And Evolution Of The Apes And Man"

See other formats


THE  XERVOUS  Sl^TLJI
sulcus, or sulcus diagonals; this connection is not ijiV'sfst in fig. 50.
The anterior part of the insula t,*   :< exposed, and it-bounding fissures, the superior limiting sulcus ^X.^. and fronto-orbital sulcus >F.O.S,<,are deep and v/eJ5 marked.    The latter ascends, and is frequently ecstinuouS with the arcuate sulcus.
The orbital sulcus  O.S.  ascends perpendicular]v in
.    *.                .
front of the f ronto-orbital sulcus on the keel of the frontal lobe.
The Sylvian fissure L.S. has 2. l&i poste/ior extremity round which the parallel sulcus P.>. winds. and the latter may also be biiid. The intraparietal sulcus (I-P.S.) is connected anteriorly to one or both of the postcentral sulci, and it runs posteriorly into the simian sulcus (S.SJ; above its horizontal part there run several small compensatory sulci. The intraparietal and simian sulci form a long, curved sulcus surrounding the upper ends of the Sylvian and parallel sulci. The parieto-occipital sulcus <P-O.S.> is not confluent with the simian sulcus, but the occipital operculuni conceals the little gyrus separating the termination of the former and the beginning of the latter (fig. 50, c>
The calcarine sulcus (C.F/; is as usual embraced by the diverging limbs of the lateral occipital sulcus
(L.O.S.). The occipito-temporal sulcus (O-T.S.) runs horizontally below the lateral occipital sulcus, and the inferior occipital sulcus (I.O.S.) is almost perpendicular to it.
Several small sulci are present on the occipital and temporal lobes besides the above-mentioned fissures.
The calcarine sulcus is not branched, but there may